Bakers, particularly those which mass produce bakery goods, often mix and form the dough for those goods well before baking. The dough is then frozen for future use. Before such frozen dough can later be baked, it must first be thawed and cured. Because it is desireable for bakery goods to cure only shortly before baking begins, the curing of any frozen dough thawed well before baking time, as well as any unfrozen dough mixed well before baking time, is commonly retarded by refrigeration. In any case, the curing is conventionally accomplished in an apparatus separate from thawing or retarding devices and a transfer of the bakery goods is necessary before curing begins.
Controlled thawing has in some cases been accomplished in thawer-retarder units which initially provide a moderately elevated temperature to thaw the frozen dough, and then maintain a "retard" temperature at which curing of the thawed dough is retarded. Such units typically include a heating system for thawing the frozen dough and a refrigeration system for maintaining a retard temperature, normally only slightly above zero degrees centigrade. Where a thawing time can be predicted, automatic timers can be used for switching the unit from its heating phase to its refrigeration phase.
After thawing, after any necessary retarding, but before the dough is baked, the bakery goods must normally be transferred for an appropriate time to a bakery proofer for curing. Transfer is normally accomplished by the removal of trays of bakery goods from racks within the retarder and placement of those trays upon racks within the proofer. Larger bakeries position the trays on wheel-mounted carts which may be transferred in their entirety from the retarder or thawer to the proofer. Carts increase the handling efficiency of the transfer operation; but in any case, such transfer represents a labor intensive step during which the bakery goods are exposed to ambient conditions within the bakery.
Proofers typically provide an enclosed atmosphere of a selected temperature and humidity in which the dough can cure or rise. Good proofing is a function of time, temperature and humidity. Conventional proofers have a steam generating unit and an air heater both located together outside the proofer interior. These proofers have experienced moisture and temperature control problems. Moreover, the droplets of condensation formed within the air handling sections of some proofers undesirably wetten the curing bakery products.
The most troublesome problem in conventional proofers is the continuing deposit of mineral residue within the steam generating system. The accumulation of such deposits adversely affects steam generation and consequently the humidity control within the system. Some steam generating designs provide for flushing the boiler during start-up. But frequent manual scouring of the steam generating equipment is often the only effective residue control measure.